This invention relates, in general, to testing apparatus and methods and, more particularly, to an apparatus and method for testing magnetic materials.
Traditionally, flux measurements have been conducted with a ballistic galvanometer that deflects a light beam. This is a slow, cumbersome, and inaccurate method.
Another method is using Hall Effect sensors along with a permanent magnet. ln this process a sample is moved at a constant speed through the magnetic field while measurements are taken with the Hall Effect device. This method is slow and inaccurate and the results of this method can be influenced by temperature.
An improvement of the Hall Effect device uses solid state devices, see DeMott, lntegrating Flux Meter With Digital Read Out, 6 I.E.E.E. Trans. On Mag., 269 (1970). This device is derived by coupling a solid-state voltage-to-frequency converter to a digital converter. This device, however, is unable to make the variety of measurements often desired and has a narrow range of operating conditions.
Further, the I.E.E.E. standard has no storage for the text results and has little or no control over the rate of rise of the current pulses used.